-LRB- CNN -RRB- -- Two U.S. spacecraft are set to crash on the moon Friday . On purpose . And we 're all invited to watch .

An artist 's rendering shows the LCROSS spacecraft , left , separating from its Centaur rocket .

NASA 's Lunar Crater Observation and Sensing Satellite is scheduled to drop its Centaur upper-stage rocket on the lunar surface at 7:31 a.m. ET .

NASA hopes the impact will kick up enough dust to help the LCROSS probe find the presence of water in the moon 's soil . Four minutes later , the LCROSS will follow through the debris plume , collecting and relaying data back to Earth before crashing into the Cabeus crater near the moon 's south pole .

The LCROSS is carrying spectrometers , near-infrared cameras , a visible camera and a visible radiometer . These instruments will help NASA scientists analyze the plume of dust -- more than 250 metric tons ' worth -- for water vapor .

The orbiting Hubble Space Telescope and NASA 's Lunar Reconnaissance Orbiter will watch , and photograph , the collisions . And hundreds of telescopes on Earth also will be focused on the two plumes . Watch animation of how the moon will be `` bombed '' ''

NASA is encouraging amateur astronomers to join the watch party .

`` We expect the debris plumes to be visible through midsized backyard telescopes -- 10 inches and larger , '' said Brian Day at NASA 's Ames Research Center at Moffett Field , California . Day is an amateur astronomer who is leading education and public outreach for the LCROSS mission .

Ames will host `` Impact Night , '' an event with music and food starting Thursday evening before a live transmission of the lunar impact will be shown around 4:30 a.m. PT Friday . Other science observatories and amateur astronomy clubs across the country will be hosting similar events . iReport : Are you planning to watch ?

`` The initial explosions will probably be hidden behind crater walls , but the plumes will rise high enough above the crater 's rim to be seen from Earth , '' Day said . The Cabeus crater lies in permanent shadow , making observations inside the crater difficult . Watch CNN 's Jeanne Moos ask if lunacy is behind the moon `` bombing '' ''

The impacts will not be visible to the naked eye or through binoculars . If you do n't have a telescope , or you live in areas where daylight will obscure the viewing , NASA TV will broadcast the crashes live . Coverage begins at 6:15 a.m. ET Friday .

The two main components of the LCROSS mission are the shepherding spacecraft and the Centaur upper stage rocket . The spacecraft will guide the rocket to its crash site .

Data from previous space missions have revealed trace amounts of water in lunar soil . The LCROSS mission seeks a definitive answer to the question of how much water is present . NASA has said it believes water on the moon could be a valuable resource in the agency 's quest to explore the solar system .

LCROSS launched with the Lunar Reconnaissance Orbiter aboard an Atlas V rocket from Cape Canaveral , Florida , on June 18 .

Friday 's lunar impact will be visible best in areas that are still dark , particularly in the Western United States .

The Fremont Peak Observatory near Monterey , California , will open up its doors early Friday to allow people to watch the event through its 30-inch telescope . It 's `` the most accessible public telescope in the -LSB- San Francisco -RSB- Bay Area , '' said Dave Samuels , the observatory 's vice president .

So far , at least 50 people have signed up , Samuels said , noting that number is `` really phenomenal , especially on a school night -LSB- and -RSB- work night . It 's really incredible . ''

Students , retirees and board members are among those scheduled to attend .

Samuels said a special low-light , infrared video camera will be hooked up to the telescope so that the audience can watch the rocket strike the moon . The observatory is in Fremont Peak State Park , which is on a list of California parks that could close because of recent budget cuts .

Samuels said he hopes Friday 's event triggers more interest in astronomy , particularly among young children , and possibly help the park to stay open .

`` It 's things like this that get kids interested -LSB- in science -RSB- , '' he said . `` It will probably be a defining moment for them . ''

Darrick Gray , who teaches atmospheric sciences at Ray-Pec High School near Kansas City , Missouri , said he 's planning to take 17 students -- all juniors and seniors -- to watch the lunar impact .

`` This is truly a once-in-a-lifetime thing , '' Gray said . He said he 's arranged for a school bus to pick up the kids early Friday and take the class to the Powell Observatory in Louisburg , Kansas .

`` It 's weather-dependent ; we 've got rain right now , '' Gray said . `` It 's going to be a call I make at 5 a.m. ''

Gray , who is also the director of the Astronomical Society of Kansas City , said his students will try to take photos of the impact through the eyepiece of their telescopes . He said he hopes the event will influence his students to pursue careers in science .

`` Being as we do live here in Missouri , we 're away from the hub -LSB- of astronomy -RSB- , '' Gray said . `` We 're not in Florida , we 're not in Texas , we 're not in Silicon Valley -- it 's not something they 're used to seeing .

`` So any time you can show them something that 's never been done , and they say , ` Oh this is pretty cool , ' I think they buy into that . ''

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A NASA spacecraft is set to drop a rocket on the moon at 7:31 a.m. ET Friday

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Four minutes later , the LCROSS probe will follow and crash onto the lunar surface

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The LCROSS probe will relay data back to Earth about water vapor in moon dust

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The debris plumes will be visible through midsize backyard telescopes